FIG. 11A and FIG. 11B each illustrates a spiral bevel gear meshing with a pinion. FIG. 12A and FIG. 12B each illustrates a face gear meshing with a pinion. The spiral bevel gear rolling contacts with the pinion on every portion on a pitch line thereof. The face gear, rolling contacts with the pinion only at a point at which a segment of a line equivalent to the pitch line of the spiral bevel gear is crossed. In recent years, attention has been paid to the face gear, since, in comparison with the spiral bevel gear, it is advantageous in terms of cost efficiency.
Methods for gear cutting of such a face gear include a plunge cut method and a tangential feed method (“Machines and Tools”, July issue, 1998, pages 16 to 20). According to the plunge cut method, in a state in which a cutter faces a work piece, the cutter is disposed in a direction in which a shaft axis of the cutter and that of the work piece cross each other; while the cutter and the work piece are rotated at the same time, the cutter is fed toward the work piece; and then, gear cutting is performed on the work piece. According to the tangential feed method, in a state in which a cutter does not face a work piece at an initial position, the cutter is disposed in a direction in which a shaft axis of the cutter and that of the work piece cross each other; while the cutter and the work piece are rotated at the same time, the cutter is fed while being reciprocally moved along a radial direction of the work piece; and then, gear cutting is performed on the work piece.
According to the methods described above, although a face gear is formed, the level of efficiency in forming a face-geared surface are not always sufficient. In the related industrial field, a demand exists for developing a method for forming a face-geared surface efficiently.
A need thus exists to provide a manufacturing method by which a face-geared surface is formed efficiently.